Organometallic compound and organic light-emitting device including the same

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
     
     wherein in Formula 1, M, L 1 , n1, n2, and R 41  to R 47  are described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2014-0054431, filed on May 7, 2014 in the Korean IntellectualProperty Office, and all the benefits accruing therefrom under 35 U.S.C.§119, the content of which is incorporated herein in its entirety byreference.

BACKGROUND

1. Field

One or more embodiments of the present disclosure relate to anorganometallic compound and an organic light-emitting device includingthe organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emitting devices thatcan provide multicolored images and have advantages such as wide viewingangles, excellent contrast, quick response times, excellent brightness,low driving voltages, and excellent response speed characteristics.

A typical OLED has a structure including an anode, a cathode, and anorganic layer disposed between the anode and the cathode and includingan emission layer (EML). A hole transporting region may be disposedbetween the anode and the EML, and an electron transporting region maybe formed between the EML and the cathode. Holes injected from the anodemove to the EML via the hole transport region, and electrons injectedfrom the cathode move to the EML via the electron transport region.Excitons are generated when carriers such as holes and electronsrecombine in the EML. When the excitons drop from an excited state to aground state, light is emitted.

Various types of organic light emitting devices are known. However,there still remains a need in OLEDs having low driving voltage, highefficiency, high brightness, and long lifespan.

SUMMARY

One or more embodiments include a novel organometallic compound and anorganic light-emitting device including the novel organometalliccompound.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments, provided is an organometalliccompound represented by Formula 1, wherein L₁ in Formula 1 includes atleast one selected from a first ligand represented by Formula 2A, asecond ligand represented by Formula 2B, and a third ligand representedby one selected from Formulae 2C, 2D, and 2E:

wherein, in Formulae 1, 2A to 2E, and 3 above,

M is selected from Ir, Pt, Os, Ti, Zr, Hf, Eu, Tb, and Tm;

CY₁ to CY₄ may be each independently a C₂-C₆₀ heterocyclic groupincluding at least one N;

Y₁ and Y₂ may be each independently selected from C or N;

X₁ may be N or CR₁,

X₂ may be N or CR₂,

X₃ may be N or CR₃,

X₄ may be N or CR₄,

X₁₁ may be N or CR₁₁,

X₁₂ may be N or CR₁₂,

X₁₃ may be N or CR₁₃,

X₁₄ may be N or CR₁₄,

X₁₅ may be N or CR₁₅, and

X₁₆ may be N or CR₁₆;

Z₃₂ may be selected from *—O—*′, *—S—*′, *—N(Q₅₁)-*′, *—C(Q₅₂)(Q₅₃)-*′,*—C(Q₅₄)=C(Q₅₅)-*′, and

b2 may be an integer selected from 1 to 10 and when b2 is 2 or greater,groups Z₃₂ may be the same or different;

R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁ to R₁₆, and Q₅₁ to Q₅₉ may be eachindependently selected from a hydrogen, a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, carboxylic acid group or asalt thereof, sulfonic acid group or a salt thereof, phosphoric acidgroup or a salt thereof, —SF₅, a substituted or unsubstituted C₁-C₆₀alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and—B(Q₆)(Q₇);

R₂₁ and R₂₂ may be each independently selected from a cyano group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group;

R₂₁ and R₂₂ may optionally bind to each other via single bond or asecond linking group represented by Formula 3;

the following conditions regarding R₂₁ and R₂₂ in Formula 2E areexcluded

i) where R₂₁ and R₂₂ are both phenyl groups,

ii) where R₂₁ and R₂₂ are both phenyl groups substituted with atert-butyl group,

iii) where R₂₁ and R₂₂ are both ethyl groups,

iv) where R₂₁ and R₂₂ are both propyl groups,

v) where R₂₁ and R₂₂ are both butyl groups, and

vi) where R₂₁ and R₂₂ are both —Si(CH₃)₃;

in Formula 1, both R₄₅ and R₄₆ are not —F;

in Formula 1, when L₁ includes the second ligand or the third ligand,each of R₄₁ to R₄₇ is not a hydrogen;

in Formula 2D, at least one selected from X₁₁ to X₁₆ is N;

a1 to a4 may be each independently integers selected from 1 to 5;

n1 may be an integer selected from 0 to 2;

n2 may be an integer selected from 1 to 3;

* and *′ are binding sites to M in Formula 1;

in Formula 2A, a bond between N and Y₁ and a bond between N and Y₂, andin Formula 2B, a bond between C and N may be each independently a singlebond or a double bond;

at least one substituent of the substituted C₁-C₆₀ alkyl group, thesubstituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group,the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₂-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₂-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group may be selected from

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, monovalent non-aromatic condensed polycyclic group,monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),—Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇);

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅) and —B(Q₂₆)(Q₂₇); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); wherein,

Q₁ to Q₇, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇ and Q₃₁ to Q₃₇ may be eachindependently selected from a hydrogen, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group.

According to another embodiment, provided is an organic light-emittingdevice including

a first electrode;

a second electrode; and

an organic layer including an emission layer (EML) disposed between thefirst electrode and the second electrode, wherein the emission layerincludes an organometallic compound represented by Formula 1.

The organometallic compound may be included in the EML, theorganometallic compound included in the EML may act as a dopant, and theEML may further include a host.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawing in which FIG. 1 is a schematicview of an organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

An organometallic compound may be represented by Formula 1. In Formula 1below, L₁ may include at least one selected from a first ligandrepresented by Formula 2A below, a second ligand represented by Formula2B below, and a third ligand represented by one selected from Formulae2C, 2D, and 2E:

In the Formulae above, * and *′ are binding sites to M in Formula 1above.

In Formula 1, M may be selected from iridium (Ir), platinum (Pt), osmium(Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), and thulium (Tm).

For example, in Formula 1, M may be Ir or Pt.

In Formulae 2A and 2B, CY₁ to CY₄ may be each independently a C₂-C₆₀heterocyclic group including at least one N.

For example, CY₁ to CY₄ may be each independently selected from apyrrole, an imidazole, a pyrazole, a thiazole, an isothiazole, anoxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, apyridazine, a quinoline, an isoquinoline, a benzoquinoline, aquinoxaline, a quinazoline, a benzimidazole, a benzoxazole, aniso-benzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, apyridoindole, a pyridofuran, and a pyridothiophene.

According to an embodiment, CY₁ above may be selected from a pyridine, apyrazine, a pyrimidine, a pyridazine, a quinoline, an isoquinoline, abenzoquinoline, a quinoxaline, a quinazoline, a pyridoindole, apyridofuran, and a pyridothiophene.

According to another embodiment, CY₂ may be an imidazole or a pyrazolyl.

According to another embodiment, CY₃ and CY₄ may be each independentlyselected from a pyridine, a pyrazine, a pyrimidine, a pyridazine, aquinoline, an isoquinoline, a benzoquinoline, a quinoxaline, or aquinazoline.

Z₁ in CY₁ and Z₂ in CY₂ may optionally bind to each other through asingle bond or a first linking group to form a saturated or anunsaturated ring, and the first linking group may be selected fromlinking groups represented by Formula 6 below:

*—(Z₃₁)_(b1)—*′  Formula 6

Z₃₁ in Formula 6 may be selected from *—O—*′, *—S—*′, *—N(Q₄₁)-*′,*—C(Q₄₂)(Q₄₃)-*′, *—C(Q₄₄)=C(Q₄₅)-*′, and

Q₄₁ to Q₄₉ may be each independently selected from a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group; and

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group; and

b1 may be an integer selected from 1 to 10 and when b1 is 2 or greater,groups Z₃₁ may be the same or different.

Descriptions of Q₄₁ to Q₄₉ may be understood by referring to thedescription of Z₁ herein.

In Formula 2A, Y₁ and Y₂ may be each independently C or N.

In Formulae 2C and 2D,

X₁ may be N or CR₁,

X₂ may be N or CR₂,

X₃ may be N or CR₃,

X₄ may be N or CR₄,

X₁₁ may be N or CR₁₁,

X₁₂ may be N or CR₁₂,

X₁₃ may be N or CR₁₃,

X₁₄ may be N or CR₁₄,

X₁₅ may be N or CR₁₅, and

X₁₆ may be N or CR₁₆.

According to an embodiment, in Formula 2C, at least one selected from X₁to X₄ may be N.

In Formula 2E, R₂₁ and R₂₂ may optionally bind to each other by a singlebond or via a second linking group represented by Formula 3.

*—(Z₃₂)_(b2)—*′  Formula 3

In Formula 3, Z₃₂ may be selected from *—O—*′, *—S—*′, *—N(Q₅₁)-*′,*—C(Q₅₂)(Q₅₃)-*′, *—C(Q₅₄)=C(Q₅₅)-*′, and

R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁ to R₁₆, and Q₅₁ to Q₅₉ may be eachindependently selected from a hydrogen, a deuterium, —F (a fluorogroup), —Cl (a chloro group), —Br (a bromo group), —I (an iodo group), ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, carboxylic acid group or asalt thereof, sulfonic acid group or a salt thereof, phosphoric acidgroup or a salt thereof, —SF₅, a substituted or unsubstituted C₁-C₆₀alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and—B(Q₆)(Q₇); and

R₂₁ and R₂₂ may be each independently selected from a cyano group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group.

According to an embodiment, the R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁ toR₁₆, and Q₅₁ to Q₅₉ may be each independently selected from

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, —SF₅, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aphenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinylgroup;

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group;

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₁-C₆₀ alkyl group substituted with at least one—F, a C₁-C₆₀ alkoxy group substituted with at least one —F, a phenylgroup, a pentalenyl group, an indenyl group, a naphthyl group, anazulenyl group, a heptalenyl group, an indacenyl group, an acenaphthylgroup, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenylgroup, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a naphthacenyl group, apicenyl group, a perylenyl group, a pentaphenyl group, a hexacenylgroup, a pentacenyl group, a rubicenyl group, a coronenyl group, anovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aphthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, an imidazopyrimidinyl group,—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇); wherein,

Q₁ to Q₇ and Q₃₁ to Q₃₇ may be each independently selected from ahydrogen, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, anaphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenylgroup, a fluorenyl group, a chrysenyl group, a carbazolyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a pyridinyl group, a pyrimidinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinazolinyl group, and a quinoxalinyl group.

According to another embodiment, the R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁to R₁₆, and Q₅₁ to Q₅₉ may be each independently selected from

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, —SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a phenyl group, a naphthyl group, a pyridinyl group, anda pyrimidinyl group;

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₁-C₂₀alkyl group substituted with at least one —F, a C₁-C₂₀ alkoxy groupsubstituted with at least one —F, a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group.

According to another embodiment, the R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁to R₁₆, and Q₅₁ to Q₅₉ may be each independently selected from

a hydrogen, —F, a cyano group, a nitro group, —SF₅, a methyl group, anethyl group, a propyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, anisohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptylgroup, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, ann-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group,an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, an n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group and a triazinyl group; and

a methyl group, an ethyl group, a propyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, ann-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an isononyl group, a sec-nonylgroup, a tert-nonyl group, an n-decanyl group, an isodecanyl group, asec-decanyl group, a tert-decanyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,a naphthyl group, a pyridinyl group, a pyrimidinyl group, or a triazinylgroup, each substituted with at least one selected from —F, a cyanogroup, and a nitro group, but they are not limited thereto.

In Formula 2E, the following conditions regarding R₂₁ and R₂₂ areexcluded:

i) where R₂₁ and R₂₂ are both phenyl groups,

ii) where R₂₁ and R₂₂ are both phenyl groups substituted with atert-butyl group,

iii) where R₂₁ and R₂₂ are both ethyl groups,

iv) where R₂₁ and R₂₂ are both propyl groups,

v) where R₂₁ and R₂₂ are both butyl groups, and

vi) where R₂₁ and R₂₂ are both —Si(CH₃)₃.

According to an embodiment, in Formula 2E, cases in which i) R₂₁ and R₂₂are not connected to each other and R₂₁ and R₂₂ are phenyl groups, andii) R₂₁ and R₂₂ are not connected to each other and R₂₁ and R₂₂ arephenyl groups substituted with one C₁-C₆₀ alkyl group may be excluded;and cases in which i) R₂₁ and R₂₂ are connected by a single bond or viaa second linking group, wherein the second linking group is *—O—*′ or*—S—*′ and all of R₂₁ and R₂₂ are phenyl groups, and ii) R₂₁ and R₂₂ areconnected by a single bond or via a second linking group, wherein thesecond linking group is *—O—*′ or *—S—*′, and all of R₂₁ and R₂₂ aresubstituted with one C₁-C₆₀ alkyl group may be excluded.

According to another embodiment, in Formula 1, at least one selectedfrom R₄₅ and R₄₆ may not be a hydrogen.

According to another embodiment, in Formula 1, R₄₅ and R₄₆ may bedifferent.

According to another embodiment, in Formula 1, at least one selectedfrom R₄₅ and R₄₆ may be —F, a cyano group, or —CF₃, but it is notlimited thereto.

In Formula 1, both R₄₅ and R₄₆ are not —F.

In Formula 1, when L₁ includes the second ligand or the third ligand,each of R₄₁ to R₄₇ is not a hydrogen.

In Formula 2D, at least one selected from X₁₁ to X₁₆ is N.

In Formula 2A, a1 represents the number of groups Z₁ and may be aninteger selected from 1 to 5. For example, a1 may be 1, 2, or 3, but itis not limited thereto.

When a1 is 2 or greater, two or more groups Z₁ may be the same ordifferent. Each of a2 to a4 represents the number of groups Z₂ to Z₄,and descriptions thereof may be understood by referring to thedescription of a1.

In Formula 1, n1 may be an integer selected from 0 to 2 and n2 may be aninteger selected from 1 to 3. When n1 is 0, L₁ is absent in Formula 1.

According to an embodiment, in Formula 1, n1 may be 0 or 1.

In Formula 2A, a bond between N and Y₁ and a bond between N and Y₂ andin Formula 2B, a bond between C and N may be each independently a singlebond or a double bond.

According to an embodiment, the first ligand may be represented by anyone selected from Formulae 2A-1 to 2A-45:

In Formulae 2A-1 to 2A-45,

Z₁, Z₂, Z₁₁ to Z₁₃, and Q₄₆ to Q₄₉ may be understood by descriptionsherein,

aa1 may be an integer selected from 1 to 4,

ab1 and ab2 may be each independently integers selected from 1 to 3, and

ac1 and ac2 may be each independently 1 or 2.

According to another embodiment, the second ligand may be represented byany one selected from Formula 2B-1 to 2B-25:

In Formulae 2B-1 to 2B-25,

descriptions of Z₃ and Z₄ may be understood by referring to thedescriptions herein, and

aa3 and aa4 may be each independently integers selected from 1 to 4,

ab3 and ab4 may be each independently integers selected from 1 to 3,

ac3 and ab4 may be each independently 1 or 2, and

* and *′ are binding sites to M in Formula 1.

According to another embodiment, the third ligand may be one selectedfrom Formulae 2C-1 to 2C-4 and 2D-1 to 2D-4:

In Formulae 2C-1 to 2C-4 and 2D-1 to 2D-4, descriptions of Z₅, Z₆, R₁ toR₄, and R₁₁ to R₁₆ may be understood by referring to the descriptionsherein.

For example, in Formulae 2A-1 to 2A-45, 2B-1 to 2B-25, 2C-1 to 2C-4, and2D-1 to 2D-4, Z₁ to Z₆, Z₁₁ to Z₁₃, R₁ to R₄, R₁₁ to R₁₆, and Q₄₆ to Q₄₉may be each independently selected from

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a phenyl group, a naphthyl group, a pyridinyl group, anda pyrimidinyl group;

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; but they are not limitedthereto.

In Formula 2E, R₂₁ and R₂₂ may be each independently selected from

a cyano group;

a C₁-C₂₀ alkyl group substituted with at least one selected from adeuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a phenyl group, anaphthyl group, a pyridinyl group, and a pyrimidinyl group;

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and

a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group;

the Q₃₁ to Q₃₇ may be each independently selected from a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenylgroup, a chrysenyl group, a carbazolyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a pyridinyl group, a pyrimidinyl group, a triazinyl group, aquinolinyl group, an isoquinolinyl group, a quinazolinyl group, and aquinoxalinyl group;

at least one selected from R₂₁ and R₂₂ may be selected from

a cyano group;

a C₁-C₂₀ alkyl group substituted with at least one selected from adeuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a phenyl group, anaphthyl group, a pyridinyl group, and a pyrimidinyl group;

a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and

a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a pentalenyl group, an indenyl group, a naphthyl group, anazulenyl group, a heptalenyl group, an indacenyl group, an acenaphthylgroup, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenylgroup, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a naphthacenyl group, apicenyl group, a perylenyl group, a pentaphenyl group, a hexacenylgroup, a pentacenyl group, a rubicenyl group, a coronenyl group, anovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aphthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group.

For example, in Formula 2E, R₂₁ and R₂₂ may be each independentlyselected from

a cyano group;

a phenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a triazinyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

a phenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a triazinyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, carboxylic acid group or asalt thereof, sulfonic acid group or a salt thereof, phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinylgroup, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinylgroup, a quinazolinyl group, a triazinyl group, a dibenzofuranyl group,and a dibenzothiophenyl group;

at least one selected from R₂₁ and R₂₂ may be selected from

a cyano group;

a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a triazinyl group, a dibenzofuranyl group, and adibenzothiophenyl group; and

a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a triazinyl group, a dibenzofuranyl group, and adibenzothiophenyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a triazinyl group, a dibenzofuranyl group, and adibenzothiophenyl group.

According to an embodiment, the third ligand may be selected fromFormula 2E(1) or 2E(2):

In Formulae 2E(1) and 2E(2),

descriptions of Z₅, Z₆, Z₃₂, and

b2 may be understood by referring to the descriptions herein;

X₃₁ may be N or CR₃₁,

X₃₂ may be N or CR₃₂,

X₃₃ may be N or CR₃₃,

X₃₄ may be N or CR₃₄,

X₃₅ may be N or CR₃₅,

X₃₆ may be N or CR₃₆,

X₃₇ may be N or CR₃₇,

X₃₈ may be N or CR₃₈, and

at least one selected from X₃₁ to X₃₈ may be N; and

descriptions of R₃₁ to R₃₈ may be each independently the same as thedescription for R₁.

According to another embodiment, the third ligand may be represented byany one selected from Formulae 2E-1 to 2E-25:

In Formulae 2E-1 to 2E-25,

descriptions of Z₅, Z₆, R₃₁ to R₃₈, and Q₅₂ to Q₅₅ may be understood byreferring to the description herein,

d1 may be an integer selected from 1 to 4,

d2 may be an integer selected from 1 to 5,

d3 may be an integer selected from 1 to 3,

d4 may be 1 or 2, and

d5 may be an integer selected from 1 to 7.

For example, in Formulae 2E-1 to 2E-25, Z₅, Z₆, R₃₁ to R₃₈, and Q₅₂ toQ₅₅ may be each independently selected from

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a phenyl group, a naphthyl group, a pyridinyl group, anda pyrimidinyl group;

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group;

a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisooxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇), wherein;

Q₁ to Q₇ may be each independently selected from a hydrogen, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, and a naphthylgroup, but they are not limited thereto.

According to an embodiment, the organometallic compound may berepresented by Formula 1A below:

In Formula 1A, descriptions of R₄₃, R₄₅, R₄₆, M, and n2 may beunderstood by referring to the descriptions herein.

For example, in Formula 1A, R₄₃, R₄₅, and R₄₆ may be each independentlyselected from

a hydrogen, —F, a cyano group, a nitro group, —SF₅, a methyl group, anethyl group, a propyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, anisohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptylgroup, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, ann-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group,an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, an n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group and a triazinyl group; and

a methyl group, an ethyl group, a propyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, ann-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an isononyl group, a sec-nonylgroup, a tert-nonyl group, an n-decanyl group, an isodecanyl group, asec-decanyl group, a tert-decanyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,a naphthyl group, a pyridinyl group, a pyrimidinyl group, and atriazinyl group, each substituted with at least one selected from —F, acyano group, and a nitro group; wherein cases in which

both R₄₅ and R₄₆ are not —F;

both R₄₅ and R₄₆ are not a hydrogen; and

n2 may be 2 or 3, but they are not limited thereto.

According to another embodiment, in Formula 1 above,

n1 is 1 or 2;

L₁ may be a ligand represented by Formula 2A-19, a ligand represented byFormula 2B-1, and a ligand represented by Formula 2E-17, but it is notlimited thereto:

In Formulae 2A-19, 2B-1, and 2E-17,

Z₁ to Z₆, R₃₁ to R₃₆, and R₃₈ may be each independently selected from

a hydrogen, —F, a cyano group, a nitro group, —SF₅, a methyl group, anethyl group, a propyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, anisohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptylgroup, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, ann-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group,an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, an n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group, and a triazinyl group; and

a methyl group, an ethyl group, a propyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, ann-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an isononyl group, a sec-nonylgroup, a tert-nonyl group, an n-decanyl group, an isodecanyl group, asec-decanyl group, a tert-decanyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,a naphthyl group, a pyridinyl group, a pyrimidinyl group, and atriazinyl group, each substituted with at least one selected from —F, acyano group, and a nitro group, and

aa1, aa3, aa4, and ac2 may be each independently 1 or 2.

The organometallic compound represented by Formula 1 may be any oneselected from Compounds 1 to 22.

Since the organometallic compound represented by Formula 1 aboveincludes Ligand 1 described as follows, the organometallic compoundrepresented by Formula 1 capable of emitting deep blue light.

In Formula 1, both R₄₅ and R₄₆ is not —F. While not wishing to be boundby theory, it is believed that, in Formula 1, when the organometalliccompound in which both R₄₅ and R₄₆ are —F is used in an organiclight-emitting device, —F may be dissociated from the organometalliccompound to form F⁻ during an operation of the organic light-emittingdevice. Since F⁻ is highly reactive, dissociation of F⁻ may cause adecrease in the lifespan of the organic light-emitting device.

However, in Formula 1, the organic light-emitting device including anorganometallic compound, in which both R₄₅ and R₄₆ are not —F, may emitdeep blue light having excellent color coordination and may have a longlifespan.

In Formula 2E defined according to the description above, R₂₁ and R₂₂may not be an “unsubstituted C₁-C₆₀ alkyl group”. As a result, anorganometallic compound including a third ligand represented by Formula2E may have excellent dispersibility to prevent the aggregation ofmolecules, and thus, an organic light-emitting device including theorganometallic compound may have high efficiency and a long lifespan dueto improvement in charge mobility.

The preparation of the organometallic compound represented by Formula 1above may be understood by one of ordinary skill in the art withreference to Synthesis Examples described below.

Accordingly, the organometallic compound represented by Formula 1 abovemay be used as an organic layer of an organic light-emitting device, forexample, as a dopant in an emission layer (EML) of the organic layer.According to another embodiment, provided is an organic light-emittingdevice including

a first electrode;

a second electrode; and

an organic layer disposed between the first electrode and the secondelectrode,

wherein the organic layer includes an EML and at least oneorganometallic compound represented by Formula 1 above.

The organic light-emitting device may include the organic layerincluding the organometallic compound represented by Formula 1 to have alow driving voltage, high efficiency, high brightness, and a longlifespan. Also, the organic light-emitting device including theorganometallic compound represented by Formula 1 above is capable ofemitting blue light having a maximum emission wavelength in a range ofabout 440 nanometers (nm) to about 500 nm, an x color coordinate in arange of about 0.16 to about 0.22, and a y color coordinate in a rangeof about 0.10 to about 0.40.

The organometallic compound represented by Formula 1 above may be usedbetween a pair of electrodes in an organic light-emitting device. Forexample, the organometallic compound represented by Formula 1 above maybe included therein. In this regard, the organometallic compound acts asa dopant and the EML may further include a host (in other words, theamount of the organometallic compound represented by Formula 1 above maybe smaller than the amount of the host).

As used herein, the expression the “(organic layer) includes at leastone organometallic compound” may be construed as meaning the “(organiclayer) may include one organometallic compound within the scope ofFormula 1 or two different organometallic compounds within the scope ofFormula 1”.

For example, the organic layer may include only Compound 1 as theorganometallic compound. In this regard, Compound 1 may be included inthe EML of the organic light-emitting device. Alternatively, the organiclayer may include Compound 1 and Compound 2 as the organometalliccompounds. In this regard, Compound 1 and Compound 2 may be included inthe same layer (for example, Compound 1 and Compound 2 may both beincluded in the EML).

The first electrode may be an anode, which is a hole injectionelectrode, and the second electrode may be a cathode, which is anelectron injection electrode.

Alternatively, the first electrode may be a cathode, which is anelectron injection electrode, and the second electrode may be an anode,which is a hole injection electrode.

For example, the first electrode may be an anode, the second electrodemay be a cathode, and the organic layer may include

i) a hole transport region disposed between the first electrode and theEML, wherein the hole transport region may include at least one selectedfrom a hole injection layer, a hole transport layer, and an electronblocking layer; and

ii) an electron transport region disposed between the EML and the secondelectrode, wherein the electron transport region may include at leastone selected from a hole blocking layer (HBL), an electron transportlayer, and an electron injection layer.

As used herein, the term “organic layer” refers to a single and/or aplurality of layers disposed between the first electrode and the secondelectrode in an organic light-emitting device. The “organic layer” mayinclude not only organic compounds but also organometallic complexesincluding metals.

FIG. 1 is a schematic view of an organic light-emitting device 10according to an embodiment. Hereinafter, a structure and a method ofmanufacturing an organic light-emitting device, according to anembodiment, will be described with reference to FIG. 1. The organiclight-emitting device 10 includes a first electrode 11, an organic layer15, and a second electrode 19, which are sequentially layered in thestated order.

A substrate may be additionally disposed under the first electrode 11 oron the second electrode 19. The substrate may be a conventional glasssubstrate or a transparent plastic substrate, each having excellentmechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, and water repellency.

The first electrode 11 may be formed by depositing or sputtering amaterial for forming the first electrode 11 on the substrate. The firstelectrode 11 may be an anode. The material for the first electrode 11may be selected from materials with a high work function for easy holeinjection. The first electrode 11 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. The materialfor the first electrode 110 may be selected from indium (In) tin (Sn)oxide (ITO), indium (In) zinc (Zn) oxide (IZO), tin (Sn) oxide (SnO₂),and zinc (Zn) oxide (ZnO). Alternatively, a metal such as magnesium(Mg), aluminum (Al), aluminum(Al)-lithium(Li) (Al—Li), calcium (Ca),magnesium (Mg)-indium (In) (Mg—In), and magnesium (Mg)-silver (Ag)(Mg—Ag).

The first electrode 11 may have a single layer structure or amulti-layer structure including two or more layers. For example, thefirst electrode 11 may have a triple-layer structure of ITO/Ag/ITO, butit is not limited thereto.

The organic layer 15 may be disposed on the first electrode 11.

The organic layer 15 may include a hole transport region, an EML, and anelectron transport region.

The hole transport region may be disposed between the first electrode 11and the EML.

The hole transport region may include at least one selected from a holeinjection layer (HIL), a hole transport layer (HTL), anelectron-blocking layer (EBL), and a buffer layer.

The hole transport region may only include an HIL or a HTL.Alternatively, the hole transport region may include a structure inwhich HIL/HTL or HIL/HTL/EBL are sequentially layered on the firstelectrode 11.

When the hole transport region includes the HIL, the HIL may be formedon the first electrode 11 by using various methods such as vacuumdeposition, spin coating, casting, and a Langmuir-Blodgett (LB) method.

When an HIL is formed by vacuum deposition, for example, the vacuumdeposition may be performed at a deposition temperature of about 100 toabout 500° C., at a vacuum degree of about 10⁻⁸ to about 10⁻³ torr, andat a deposition rate of about 0.01 Angstroms per second (Å/sec) to about100 Å/sec, though the conditions may vary depending on a compound thatis used as a hole injection material and a structure and thermalproperties of a desired HIL.

When an HIL is formed by spin coating, the spin coating may be performedat a coating rate of about 2,000 revolutions per minute (rpm) to about5,000 rpm, and at a temperature of about 80° C. to 200° C. for removinga solvent after the spin coating, though the conditions may varydepending on a compound that is used as a hole injection material and astructure and thermal properties of a desired HIL.

The conditions for forming the HTL and EBL may be inferred based on theconditions for forming the HIL.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB, 3-NPB, TPD, a spiro-TPD, a spiro-NPB,α-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),polyaniline/dodecylbenzene sulfonic acid (Pani/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (Pani/CSA),(polyaniline)/poly(4-styrenesulfonate) (PANI/PSS), a compoundrepresented by Formula 201 below, and a compound represented by Formula202 below:

In Formula 201, Ar₁₀₁ and Ar₁₀₂ may be each independently selected from

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenyl group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenyl group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group, each substituted with at least oneselected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

In Formula 201, xa and xb may be each independently an integer from 0 to5, or 0, 1, or 2. For example, xa may be 1 and xb may be 0, but they arenot limited thereto.

In Formulae 201 and 202, R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄may be each independently one of

a hydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₁₀ alkyl group (for example, a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, and a hexylgroup), and a C₁-C₁₀ alkoxy group (for example, a methoxy group, anethoxy group, a propoxy group, a butoxy group, and a pentoxy group);

a C₁-C₁₀ alkyl group and a C₁-C₁₀ alkoxy group, each substituted with atleast one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, and a phosphoric acidgroup or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group, but they are notlimited thereto.

In Formula 201, R₁₀₉ may be selected from

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup, each substituted with at least one selected from a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, and a C₁-C₂₀ alkoxy group.

According to an embodiment, the compound represented by Formula 201 maybe represented by Formula 201A, but it is not limited thereto:

In Formula 201A, descriptions of R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ may be asdescribed above.

For example, the compound represented by Formula 201 and the compoundrepresented by Formula 202 may include Compounds HT1 to HT20, but theyare not limited thereto:

A thickness of the hole transport region may be about 100 Angstroms (Å)to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When thehole transport region includes the HIL and the HTL, a thickness of theHIL may be about 50 Å to about 10,000 Å, for example, about 100 Å toabout 1,000 Å, a thickness of the HTL may be about 50 Å to about 2,000Å, for example, about 100 Å to about 1,500 Å. When the thicknesses ofthe hole transport region, the HIL, and the HTL are within the rangesdescribed above, satisfactory hole transporting properties may beobtained without a substantial increase in a driving voltage.

The hole transport region may further include, in addition to theabove-mentioned materials, a charge-generating material for theimprovement of conductive properties. The charge-generating material maybe homogeneously or non-homogeneously dispersed throughout the holetransport region.

The charge-generating material may be, for example, a p-dopant. Thep-dopant may be one selected from a quinone derivative, a metal oxide,and a cyano group-containing compound, but it is not limited thereto.For example, non-limiting examples of the p-dopant are a quinonederivative, such as tetracyanoquinonedimethane (TCNQ) or2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ); ametal oxide, such as a tungsten oxide or a molybdenum oxide; and theCompound HT-D1 illustrated below, but it is not limited thereto.

The hole transport region may further include a buffer layer.

The buffer layer may compensate for an optical resonance distanceaccording to a wavelength of light emitted from the EML to improve theefficiency of an organic light-emitting device.

An EML may be formed on the hole transport region by using variousmethods, such as vacuum deposition, spin coating, casting, or an LBmethod. When the EML is formed by vacuum deposition or spin coating,deposition and coating conditions for the EML may be similar to theconditions for forming the HIL, though the conditions may vary dependingon the compound used.

The EML may include a host and a dopant, and the dopant may include theorganometallic compound represented by Formula 1 above.

The host may include at least one selected from TPBi, TBADN, AND (alsoknown as “DNA”), CBP, CDBP, and TCP:

When the EML includes the host and the dopant, the amount of the dopantmay be selected from a range of about 0.01 parts by weight to about 15parts by weight based on 100 parts by weight of the host, but the amountis not limited thereto.

A thickness of the EML may be about 100 Å to about 1,000 Å, for example,about 200 Å to about 600 Å. When the thickness of the EML is within thisrange, excellent light-emission characteristics may be obtained withouta substantial increase in driving voltage.

Then, an electron transport region may be disposed on the EML.

The electron transport region may include at least one selected from anHBL, an ETL, and an EIL, but is not limited thereto.

For example, the electron transport region may have a structure ofHBL/ETL/EIL or ETL/EIL, but it is not limited thereto. The ETL may havea single layer structure or a multi-layer structure including two ormore different materials.

Conditions for forming the HBL, ETL, and EIL of the electron transportregion are as the conditions described for forming the HIL.

When the electron transport region includes an HBL, the HBL may, forexample, include at least one selected from BCP and Bphen, but it is notlimited thereto.

A thickness of the HBL may be in a range of about 20 Å to about 1,000 Å,for example, about 30 Å to about 300 Å. When the thickness of the HBL iswithin the range described above, the HBL may have excellent holeblocking characteristics without a substantial increase in drivingvoltage.

The ETL may include at least one selected from BCP and Bphen, and mayfurther include at least one selected from Alq₃, Balq, TAZ, and NTAZ.

Alternatively, the ETL may include at least one selected from CompoundsET1 and ET2, but it is not limited thereto.

A thickness of the ETL may be in a range of about 100 Å to about 1,000Å, for example, about 150 Å to about 500 Å. When the thickness of theETL is within the range described above, the ETL may have satisfactoryelectron transportation characteristics without a substantial increasein driving voltage.

Also, the ETL may further include, in addition to the materialsdescribed above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complexmay include, for example, the Compound ET-D1 (lithium quinolate, LiQ) orET-D2.

The electron transport region may include an EIL that facilitateselectron injection from the second electrode 19.

A thickness of the EIL may be in a range of about 1 Å to about 100 Å,for example, about 3 Å to about 90 Å. When the thickness of the EIL iswithin the range described above, the EIL may have satisfactory electrontransportation characteristics without a substantial increase in drivingvoltage.

The second electrode 19 is disposed on the organic layer 15 having thestructure described above. The second electrode 19 may be a cathode. Amaterial for the second electrode 19 may be a material having a low workfunction, and such a material may be a metal, an alloy, an electricallyconductive compound, or a mixture thereof. Detailed examples of thematerial for forming the second electrode 19 are Li, Mg, Al, Al—Li, Ca,Mg—In, and Mg—Ag. Alternatively, ITO or IZO may be used to form atransmissive second electrode 19 to manufacture a top emissionlight-emitting device.

Hereinbefore, the organic light-emitting device has been described withreference to FIG. 1, but the organic light-emitting device is notlimited thereto.

A C₁-C₆₀ alkyl group used herein refers to a linear or branchedaliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms.Detailed examples thereof are a methyl group, an ethyl group, a propylgroup, an isobutyl group, a sec-butyl group, a tert-butyl group, apentyl group, an iso-amyl group, and a hexyl group. A C₁-C₆₀ alkyleneused herein refers to a divalent group having the same structure as theC₁-C₆₀ alkyl group.

A C₁-C₆₀ alkoxy group used herein refers to a monovalent grouprepresented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group). Detailedexamples thereof are a methoxy group, an ethoxy group, and an isopropoxygroup.

A C₂-C₆₀ alkenyl group used herein refers to a hydrocarbon group formedby substituting at least one carbon double bond in the middle or at theterminal of the C₂-C₆₀ alkyl group. Detailed examples thereof are anethenyl group, a propenyl group, and a butenyl group. A C₂-C₆₀alkenylene group used herein refers to a divalent group having the samestructure as the C₂-C₆₀ alkenyl group.

A C₂-C₆₀ alkynyl group used herein refers to a hydrocarbon group formedby substituting at least one carbon triple bond in the middle or at theterminal of the C₂-C₆₀ alkyl group. Detailed examples thereof are anethynyl group and a propynyl group. A C₂-C₆₀ alkynylene group usedherein refers to a divalent group having the same structure as theC₂-C₆₀ alkynyl group.

A C₃-C₁₀ cycloalkyl group used herein refers to a monovalent hydrocarbonmonocyclic group having 3 to 10 carbon atoms. Detailed examples thereofare a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, acyclohexyl group, and a cycloheptyl group. A C₃-C₁₀ cycloalkylene groupused herein refers to a divalent group having the same structure as theC₃-C₁₀ cycloalkyl group.

A C₃-C₁₀ heterocycloalkyl group used herein refers to a monovalentmonocyclic group having at least one heteroatom selected from N, O, P,and S as a ring-forming atom and 3 to 10 carbon atoms. Detailed examplesthereof are tetrahydrofuranyl and tetrahydrothiophenyl. A C₃-C₁₀heterocycloalkylene group used herein refers to a divalent group havingthe same structure as the C₃-C₁₀ heterocycloalkyl group.

A C₃-C₁₀ cycloalkenyl group used herein refers to a monovalentmonocyclic group that has 3 to 10 carbon atoms and at least one doublebond in the ring thereof, and which is not aromatic. Detailed examplesthereof are a cyclopentenyl group, a cyclohexenyl group, and acycloheptenyl group. A C₃-C₁₀ cycloalkenylene group used herein refersto a divalent group having the same structure as the C₃-C₁₀ cycloalkenylgroup.

A C₂-C₁₀ heterocycloalkenyl group used herein refers to a monovalentmonocyclic group that has at least one heteroatom selected from N, O, P,and S as a ring-forming atom, 2 to 10 carbon atoms, and at least onedouble bond in its ring. Detailed examples of the C₂-C₁₀heterocycloalkenyl group are a 2,3-dihydrofuranyl group and a2,3-dihydrothiophenyl group. A C₂-C₁₀ heterocycloalkenylene group usedherein refers to a divalent group having the same structure as theC₂-C₁₀ heterocycloalkenyl group.

A C₆-C₆₀ aryl group used herein refers to a monovalent group having acarbocyclic aromatic system having 6 to 60 carbon atoms, and a C₆-C₆₀arylene group used herein refers to a divalent group having acarbocyclic aromatic system having 6 to 60 carbon atoms. Detailedexamples of the C₆-C₆₀ aryl group are a phenyl group, a naphthyl group,an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and achrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene groupeach include two or more rings, the rings may be fused to each other.

A C₂-C₆₀ heteroaryl group used herein refers to a monovalent grouphaving a carbocyclic aromatic system that has at least one heteroatomselected from N, O, P, and S as a ring-forming atom, and 2 to 60 carbonatoms. A C₂-C₆₀ heteroarylene group used herein refers to a divalentgroup having a carbocyclic aromatic system that has at least oneheteroatom selected from N, O, P, and S as a ring-forming atom, and 2 to60 carbon atoms. Detailed examples of the C₂-C₆₀ heteroaryl group are apyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, and an isoquinolinylgroup. If the C₂-C₆₀ heteroaryl group and the C₂-C₆₀ heteroarylene groupeach include two or more rings, the rings may be fused to each other.

A C₆-C₆₀ aryloxy group used herein indicates —OA₁₀₂ (wherein A₁₀₂ is theC₆-C₆₀ aryl) and a C₆-C₆₀ arylthio group used herein indicates —SA₁₀₃(wherein A₁₀₃ is the C₆-C₆₀ aryl group).

A monovalent non-aromatic condensed polycyclic group (for example,having 8 to 60 carbon atoms) used herein refers to a monovalent groupthat has two or more rings condensed to each other, only carbon atoms asring-forming atoms, and which is non-aromatic in the entire molecularstructure. A detailed example of the monovalent non-aromatic condensedpolycyclic group is a fluorenyl group. A divalent non-aromatic condensedpolycyclic group used herein refers to a divalent group having the samestructure as the monovalent non-aromatic condensed polycyclic group.

A monovalent non-aromatic condensed heteropolycyclic group (for example,having 2 to 60 carbon atoms) used herein refers to a monovalent groupthat has two or more rings condensed to each other, has a heteroatomselected from N, O P, and S, other than carbon atoms, as a ring formingatom, and which is non-aromatic in the entire molecular structure.Detailed examples of the monovalent non-aromatic condensedheteropolycyclic group are a carbazolyl group. A divalent non-aromaticcondensed heteropolycyclic group used herein refers to a divalent grouphaving the same structure as the monovalent non-aromatic condensedheteropolycyclic group.

As used herein, at least one substituent of the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₂-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇);

a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group, each substituted with atleast one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and—B(Q₂₆)(Q₂₇); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅) and —B(Q₃₆)(Q₃₇); wherein

Q₁ to Q₇, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ may be eachindependently hydrogen, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

According to an embodiment, as used herein, at least one substituent ofthe substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenylgroup, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substitutedC₂-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenylgroup, the substituted C₂-C₁₀ heterocycloalkenyl group, the substitutedC₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substitutedC₆-C₆₀ arylthio group, the substituted C₂-C₆₀ heteroaryl group, thesubstituted monovalent non-aromatic condensed polycyclic group, and thesubstituted monovalent non-aromatic condensed heteropolycyclic group maybe selected from

a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and—B(Q₁₆)(Q₁₇);

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl, a C₂-C₆₀ alkenyl, a C₂-C₆₀alkynyl, a C₁-C₆₀ alkoxy, phenyl, naphthyl, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(C₂₄)(C₂₅), and —B(Q₂₆)(Q₂₇); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇); wherein,

Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ may be each independentlyhydrogen, a C₁-C₆₀ alkyl, a C₂-C₆₀ alkenyl, a C₂-C₆₀ alkynyl, a C₁-C₆₀alkoxy, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cycloheptenyl group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl, an imidazopyridinyl group,and an imidazopyrimidinyl group.

Hereinafter, an organic light-emitting device according to an embodimentwill be described in detail with reference to Synthesis Examples andExamples. The wording “B was used instead of A” used in describingSynthesis Examples means that the molar amount of B used was identicalto the molar amount of A.

EXAMPLES Synthesis Example 1 Synthesis of Compound 1

Synthesis of Ligand 1(1)

22.5 grams (g) of Intermediate 1(1) (0.15 moles (mol)) and 25.8 g ofIntermediate 1(2) (0.15 mol) were mixed with 200 milliliters (mL) of THFin a 1 liter (L) round bottom flask loaded with an agitator under anitrogen atmosphere. 150 mL of 2 molar (M) potassium carbonate aqueoussolution, followed by 6 g of tetrakis(triphenylphosphine)palladium(0)(36.68 mmol) was added, and the resulting mixture was heated underreflux for 12 hours under a nitrogen atmosphere. After completion of thereaction, the organic layer was separated from the mixture. The solventwas removed therefrom, and column chromatography was used to obtain 20.8g of Ligand 1(1) (yield of 70%).

Synthesis of Intermediate 1(4)

19.9 g (0.1 mol) of Ligand 1(1), 13.16 g of iridium chloride (0.044mol), 180 mL of THF, and 55 mL of distilled water were mixed togetherand heated under reflux for 20 hours to obtain Intermediate 1(3). 11.31g of AgCF₃SO₃ (0.044 mol) and 200 mL of isopropanol were added toIntermediate 1(3), and the product obtained therefrom was heated underreflux to for 12 hours to obtain 32 g of Intermediate 1(4) (yield of86%).

Synthesis of Compound 1

32 g of Intermediate 1(4) (0.037 mol), 7.33 g of Ligand 1(1) (0.037mol), and 250 mL of diglyme were heat refluxed in a 1 L round bottomflask to obtain 23.5 g of Compound 1 (yield of 81%).

¹H NMR (300 MHz, CDCl₃, rt): δ 8.66 (d, J=8.50 Hz, 4H), 8.02 (d, J=7.35Hz, 2H), 7.41-7.55 (m, 4H), 7.12 (d, J=7.30, 2 H), 3.15 (s, 9H), 2.53(s, 9H), 2.35 (s, 9H).

Synthesis Example 2 Synthesis of Compound 2

Synthesis of Ligand 2(1)

Ligand 2(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate2(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 2(4)

Ligand 2(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand2(1) was used instead of Ligand 1(1).

Synthesis of Compound 2

10 g of Compound 2 (synthesis yield of 35%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 2(4) and Ligand 2(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.32 (d, J=8.05 Hz, 2H), 8.0 (d, J=7.50Hz, 2H), 7.82-7.90 (m, 3H), 7.56 (d, J=7.05 Hz, 2H), 7.01-7.26 (m, 4H),5.80 (d, J=7.35 Hz, 2H), 2.60 (s, 27H), 2.58 (d, 27H).

Synthesis Example 3 Synthesis of Compound 3

Synthesis of Ligand 3(1)

Ligand 3(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate3(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 3(4)

Intermediate 3(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand3(1) was used instead of Ligand 1(1).

Synthesis of Compound 3

10 g of Compound 3 (synthesis yield of 33%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 3(4) and Ligand 3(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.35 (d, J=8.15 Hz, 2H), 8.13 (d, J=7.80Hz, 2H), 7.76-7.95 (m, 5H), 7.67 (d, J=7.50 Hz, 2H), 6.91 (d, J=5.65 Hz,2H), 5.80 (d, J=7.55 Hz, 2H).

Synthesis Example 4 Synthesis of Compound 4

Synthesis of Ligand 4(1)

Ligand 4(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate4(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 4(4)

Intermediate 4(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand4(1) was used instead of Ligand 1(1).

Synthesis of Compound 4

5 g of Compound 4 (synthesis yield of 22%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 4(4) and Ligand 4(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.65 (d, J=8.50 Hz, 2H), 8.03 (d, J=7.80Hz, 2H), 7.75-7.85 (m, 5H), 7.30-7.38 (m, 4H), 6.91 (d, J=5.65 Hz, 2H).

Synthesis Example 5 Synthesis of Compound 5

Synthesis of Ligand 5(1)

Ligand 5(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate5(1) was used instead of Intermediate 1(1).

Synthesis of Intermediate 5(4)

Ligand 5(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand5(1) was used instead of Ligand 1(1).

Synthesis of Compound 5

5 g of Compound 5 (synthesis yield of 19%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 5(4) and Ligand 5(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.60 (d, J=8.50 Hz, 2H), 8.14 (d, J=7.50Hz, 2H), 7.70-7.83 (m, 4H), 7.35-7.45 (m, 2H), 6.68 (d, J=7.60 Hz, 2H),3.15 (s, 9H).

Synthesis Example 6 Synthesis of Compound 6

Synthesis of Ligand 6(1)

Ligand 6(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate6(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 6(4)

Intermediate 6(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand6(1) was used instead of Ligand 1(1).

Synthesis of Compound 6

3 g of Compound 6 (synthesis yield of 18%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 6(4) and Ligand 6(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 9.15 (d, J=8.59 Hz, 2H), 8.63 (d, J=8.50Hz, 2H), 8.13 (d, J=7.75 Hz, 2H), 7.74-7.87 (m, 4H), 7.33-7.42 (m, 6H),6.94 (d, J=5.65 Hz, 2H).

Synthesis Example 7 Synthesis of Compound 7

Synthesis of Ligand 7(1)

Ligand 7(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate6(1) was used instead of Intermediate 1(1).

Synthesis of Intermediate 7(4)

Intermediate 7(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand7(1) was used instead of Ligand 1(1).

Synthesis of Compound 7

3 g of Compound 7 (synthesis yield of 8%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 7(4) and Ligand 7(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 9.09 (d, J=8.55 Hz, 2H), 8.66 (d, J=8.45Hz, 2H), 8.02 (d, J=7.66 Hz, 2H), 7.72-7.68 (m, 3H), 7.30-7.39 (m, 4H),7.02 (d, J=5.65 Hz, 2H), 2.36 (s, 9H).

Synthesis Example 8 Synthesis of Compound 8

Synthesis of Ligand 8(1)

Ligand 8(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate8(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 8(4)

Intermediate 8(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand8(1) was used instead of Ligand 1(1).

Synthesis of Compound 8

3 g of Compound 8 (synthesis yield of 25%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 8(4) and Ligand 8(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.65 (d, J=8.59 Hz, 2H), 8.43 (d, J=8.50Hz, 2H), 8.03 (d, J=7.36 Hz, 2H), 7.58-7.85 (m, 6H), 7.30-7.39 (m, 6H).

Synthesis Example 9 Synthesis of Compound 9

Synthesis of Ligand 9(1)

Ligand 9(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate9(1) was used instead of Intermediate 1(1).

Synthesis of Intermediate 9(4)

Intermediate 9(4) was synthesized in the same manner as in the synthesismethod of Intermediate 1(4) in Synthesis Example 1, except that Ligand9(1) was used instead of Ligand 1(1).

Synthesis of Compound 9

3 g of Compound 9 was synthesized in the same manner as in the synthesismethod of Compound 1 in Synthesis Example 1, except that Intermediate9(4) and Ligand 9(1) were used instead of Intermediate 1(4) and Ligand1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.66 (d, J=8.60 Hz, 2H), 8.44 (d, J=8.45Hz, 2H), 8.05 (d, J=7.38 Hz, 2H), 7.68-7.76 (m, 4H), 7.28-7.38 (m, 5H),2.35 (s, 9H).

Synthesis Example 10 Synthesis of Compound 12

Synthesis of Ligand 12(1)

Ligand 12(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate12(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 12(4)

Intermediate 12(4) was synthesized in the same manner as in thesynthesis method of Intermediate 1(4) in Synthesis Example 1, exceptthat Ligand 12(1) was used instead of Ligand 1(1).

Synthesis of Compound 12

3 g of Compound 12 (Synthesis yield of 10%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 12(4) and Ligand 12(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.82 (d, J=8.59 Hz, 2H), 8.64 (d, J=8.50Hz, 2H), 8.02 (d, J=7.36 Hz, 2H), 7.48-7.85 (m, 6H), 7.30-7.40 (m, 6H).

Synthesis Example 11 Synthesis of Compound 14

Synthesis of Ligand 14(1)

Ligand 14(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate14(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 14(4)

Intermediate 14(4) was synthesized in the same manner as in thesynthesis method of Intermediate 1(4) in Synthesis Example 1, exceptthat Ligand 14(1) was used instead of Ligand 1(1).

Synthesis of Compound 14

5 g of Compound 14 (Synthesis yield of 12%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 14(4) and Ligand 14(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.65 (d, J=8.50 Hz, 2H), 8.03 (d, J=7.80Hz, 2H), 7.85-7.94 (m, 5H), 7.30-7.38 (m, 6H).

Synthesis Example 12 Synthesis of Compound 15

Synthesis of Ligand 15(1)

Ligand 15(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate15(1) was used instead of Intermediate 1(1).

Synthesis of Intermediate 15(4)

Intermediate 15(4) was synthesized in the same manner as in thesynthesis method of Intermediate 1(4) in Synthesis Example 1, exceptthat Ligand 15(1) was used instead of Ligand 1(1).

Synthesis of Compound 15

3 g of Compound 15 (Synthesis yield of 11%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 15(4) and Ligand 15(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.67 (d, J=8.55 Hz, 2H), 8.05 (d, J=7.73Hz, 2H), 7.85-7.96 (m, 5H), 7.31-7.39 (m, 6H), 3.13 (s, 9H).

Synthesis Example 13 Synthesis of Compound 17

Synthesis of Ligand 17(1)

Ligand 17(1) was synthesized in the same manner as in the synthesismethod of Ligand 1(1) in Synthesis Example 1, except that Intermediate17(1) and Intermediate 2(2) were used instead of Intermediate 1(1) andIntermediate 1(2), respectively.

Synthesis of Intermediate 17(4)

Intermediate 17(4) was synthesized in the same manner as in thesynthesis method of Intermediate 1(4) in Synthesis Example 1, exceptthat Ligand 17(1) was used instead of Ligand 1(1).

Synthesis of Compound 17

5 g of Compound 17 (Synthesis yield of 15%) was synthesized in the samemanner as in the synthesis method of Compound 1 in Synthesis Example 1,except that Intermediate 17(4) and Ligand 17(1) were used instead ofIntermediate 1(4) and Ligand 1(1), respectively.

¹H NMR (300 MHz, CDCl₃, rt): δ 8.68 (d, J=8.50 Hz, 2H), 8.08 (d, J=7.80Hz, 2H), 7.82-7.96 (m, 5H), 7.30-7.43 (m, 6H).

Evaluation Example 1 Evaluation of HOMO, LUMO, Triplet (T1) Energy andMaximum Emission Wavelength

Methods described in Table 1 below were used to measure the HOMO energylevel, LUMO energy level, triplet energy, and maximum emissionwavelength of each compound below.

TABLE 1 Method of measuring Cyclic voltammetry (CV) (electrolyte: 0.1MBu₄NClO₄/solvent: CH₂Cl₂)/ HOMO energy level electrode: 3-electrodesystem (working electrode: GC, reference electrode: Ag/AgCl, auxiliaryelectrode: Pt)) was used to obtain a voltage (volts, V) - current(amperes, A) graph of each compound and the HOMO energy level of thecompound was calculated from the reduction onset in the graph. Method ofmeasuring Each compound was diluted in CHCl₃ to a concentration of 1 ×10⁻⁵M and its LUMO energy level UV absorption spectrum was measured atroom temperature by using a Shimadzu UV-350 spectrometer and the LUMOenergy level was calculated from edges of the absorption spectrum byusing an optical band gap (Eg). Method of measuring A mixture of tolueneand each compound (1 milligram (mg) of each triplet energy compound wasdissolved in 3 cubic centimeters (cc) toluene) was added to a quartzcell and then nitrogen (N) (at 77 Kelvins, K) was added thereto. Aphotoluminescence measuring apparatus was used to measurephotoluminescence spectra, and the photoluminescence spectra werecompared with those at room temperature to analyze only the peaks thatare observed at a low temperature and calculate the T₁ energy level.Method of measuring The compounds were diluted in toluene to aconcentration of 10 millimolar maximum emission (mM) and an ISC PC1spectrofluorometer loaded with a xenon (Xe) lamp wavelength was used tomeasure photoluminescence (PL) of the compounds in a solution.

TABLE 2 HOMO T₁ Maximum (electron energy emission Compound volt, LUMOlevel wavelength No. eV) (eV) (eV) (nm) 1 −5.21 −1.47 2.49 498 2 −5.51−1.49 2.51 494 3 −6.57 −3.26 2.54 489 4 −6.18 −2.58 2.62 474 5 −6.03−2.41 2.63 471 6 −5.79 −2.18 2.64 469 7 −5.65 −2.04 2.65 468 8 −5.73−2.15 2.63 472 9 −5.55 −1.98 2.55 486 12 −6.05 −2.48 2.62 472 14 −6.51−2.91 2.62 473 15 −6.35 −2.76 2.62 473 17 5.93 1.47 2.78 490

It may be concluded from the data shown in Table 2 that the compoundshave electrooptical properties that are suitable as a material for anorganic light-emitting device.

Evaluation Example 2 Evaluation of Photoluminescence Quantum Yields(PLQY) and Color Coordination

A C₂H₄Cl₂ solution of PMMA and each of the compounds synthesized asdescribed above were mixed (8 percent by weight (wt %)), and mixturesobtained therefrom were coated on a quartz substrate by using a spincoater, heat-treated in an oven at a temperature of 80° C., and cooledto room temperature to obtain films. The films obtained therefrom wereused to evaluate PLQY and color coordination of each compound. PLQY andcolor coordination in a film of the compound were evaluated by using aHamamatsu Photonics absolute PL quantum yield measurement system loadedwith a Xe light source, a monochromator, a photonic multichannelanalyzer, and an integrating sphere, and using PLQY measurement software(Hamamatsu Photonics, Ltd., Shizuoka, Japan). The same processes wererepeated for other compounds and PLQY and a color coordination filmobtained therefrom are shown in Table 3 below.

TABLE 3 PLQY Compound No. (%) X-coordinate Y-coordinate 1 85 0.17 0.38 282 0.17 0.37 3 87 0.16 0.36 4 89 0.16 0.32 5 90 0.16 0.31 6 78 0.16 0.307 79 0.16 0.30 8 75 0.16 0.32 9 74 0.17 0.35 12 59 0.16 0.32 14 69 0.160.31 15 81 0.17 0.32 17 71 0.17 0.32

It may be concluded from the data shown in Table 3 that the compoundshave electrooptical properties that are suitable as a material for anorganic light-emitting device.

As described above, according to the one or more of the aboveembodiments, the organometallic compounds have excellent electricalproperties and thermal stability and thus, an organic light-emittingdevice including the organometallic compounds may have a low drivingvoltage, high efficiency, high brightness, and a long lifespan.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present disclosure as definedby the following claims.

What is claimed is:
 1. An organometallic compound represented by Formula1, wherein L₁ in Formula 1 comprises at least one selected from a firstligand represented by Formula 2A, a second ligand represented by Formula2B, and a third ligand represented by one selected from Formulae 2C, 2D,and 2E:

in Formulae 1, 2A to 2E, and 3 above, M is selected from Ir, Pt, Os, Ti,Zr, Hf, Eu, Tb, and Tm; CY₁ to CY₄ are each independently a C₂-C₆₀heterocyclic group comprising at least one N; Y₁ and Y₂ are eachindependently selected from C or N; X₁ is N or CR₁, X₂ is N or CR₂, X₃is N or CR₃, X₄ is N or CR₄, X₁₁ is N or CR₁₁, X₁₂ is N or CR₁₂, X₁₃ isN or CR₁₃, X₁₄ is N or CR₁₄, X₁₅ is N or CR₁₅, and X₁₆ is N or CR₁₆; Z₃₂is selected from *—O—*′, *—S—*′, *—N(Q₅₁)-*′, *—C(Q₅₂)(Q₅₃)-*′,*—C(Q₅₄)=C(Q₅₅)-*′, and

b2 is an integer selected from 1 to 10, and when b2 is 2 or greater,groups Z₃₂ are the same or different; R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄,R₁₁ to R₁₆, and Q₅ to Q₅₉ are each independently selected from ahydrogen, a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, —SF₅, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇); R₂₁and R₂₂ are each independently selected from a cyano group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, and asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group; and R₂₁ and R₂₂ optionally bind to each othervia a single bond or a second linking group represented by Formula 3;provided that the following conditions regarding R₂₁ and R₂₂ in Formula2E are excluded i) where R₂₁ and R₂₂ are both phenyl groups, ii) whereR₂₁ and R₂₂ are both phenyl groups substituted with a tert-butyl group,iii) where R₂₁ and R₂₂ are both ethyl groups, iv) where R₂₁ and R₂₂ areboth propyl groups, v) where R₂₁ and R₂₂ are both butyl groups, and vi)where R₂₁ and R₂₂ are both —Si(CH₃)₃; in Formula 1, both R₄₅ and R₄₆ arenot —F; in Formula 1, when L₁ includes the second ligand or the thirdligand, each of R₄₁ to R₄₇ is not a hydrogen; in Formula 2D, at leastone selected from X₁₁ to X₁₆ is N; a1 to a4 are each independentlyintegers selected from 1 to 5; n1 is an integer selected from 0 to 2; n2is an integer selected from 1 to 3; * and *′ are binding sites to M inFormula 1; in Formula 2A, a bond between N and Y₁ and a bond between Nand Y₂, and in Formula 2B, a bond between C and N are each independentlya single bond or a double bond; at least one substituent of thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group,the substituted C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₂-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthiogroup, the substituted C₂-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group is selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted withat least one selected from a deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₂-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), and —B(Q₁₆)(Q₁₇); C₃-C₁₀ cycloalkylgroup, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least oneselected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), and—B(Q₂₆)(Q₂₇); and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and —B(Q₃₆)(Q₃₇);wherein, Q₁ to Q₇, Q₁₁ to Q₁₇, Q₂₁ to Q₂₇, and Q₃₁ to Q₃₇ are eachindependently selected from a hydrogen, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₂-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group.
 2. The organometalliccompound of claim 1, wherein CY₁ to CY₄ are each independently selectedfrom a pyrrole, an imidazole, a pyrazole, a thiazole, an isothiazole, anoxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, apyridazine, a quinoline, an isoquinoline, a benzoquinoline, aquinoxaline, a quinazoline, a benzimidazole, a benzoxazole, aniso-benzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, apyridoindole, a pyridofuran, and a pyridothiophene.
 3. Theorganometallic compound of claim 1, wherein in Formula 2C above, atleast one of X₁ to X₄ is N.
 4. The organometallic compound of claim 1,wherein R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁ to R₁₆, and Q₅₁ to Q₅₉ areeach independently selected from a hydrogen, a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, —SF₅, a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group and a C₁-C₆₀ alkoxy group;a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aphenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinylgroup; a phenyl group, a pentalenyl group, an indenyl group, a naphthylgroup, an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group(phenazinyl), a benzoimidazolylgroup, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₁-C₆₀ alkyl group substitutedwith at least one —F, a C₁-C₆₀ alkoxy group substituted with at leastone —F, a phenyl group, a pentalenyl group, an indenyl group, a naphthylgroup, an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), and—B(Q₃₆)(Q₃₇); and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇); wherein,Q₁ to Q₇ and Q₃₁ to Q₃₇ are each independently selected from a hydrogen,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, afluorenyl group, a chrysenyl group, a carbazolyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a pyridinyl group, a pyrimidinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, aquinazolinyl group, and a quinoxalinyl group.
 5. The organometalliccompound of claim 1, wherein R₄₁ to R₄₇, Z₁ to Z₆, R₁ to R₄, R₁₁ to R₁₆,and Q₅₁ to Q₅₉ are each independently selected from a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, —SF₅, a C₁-C₂₀alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and aC₁-C₂₀ alkoxy group, each substituted with at least one selected from adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a phenyl group, anaphthyl group, a pyridinyl group, and a pyrimidinyl group; a phenylgroup, a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₁-C₂₀ alkyl groupsubstituted with at least one —F, a C₁-C₂₀ alkoxy group substituted withat least one —F, a phenyl group, a naphthyl group, a fluorenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolylgroup, a thiophenyl group, a furanyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isooxazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolylgroup, an indazolyl group, a purinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group. 6.The organometallic compound of claim 1, wherein R₄₁ to R₄₇, Z₁ to Z₆, R₁to R₄, R₁₁ to R₁₆, and Q₅₁ to Q₅₉ are each independently selected from ahydrogen, —F, a cyano group, a nitro group, —SF₅, a methyl group, anethyl group, a propyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, anisohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptylgroup, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, ann-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group,an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group, and a triazinyl group; and amethyl group, an ethyl group, a propyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a sec-pentyl group, a tert-pentyl group, ann-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group,an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an isononyl group, a sec-nonylgroup, a tert-nonyl group, an n-decanyl group, an isodecanyl group, asec-decanyl group, a tert-decanyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,a naphthyl group, a pyridinyl group, a pyrimidinyl group, and atriazinyl group, each substituted with at least one selected from —F, acyano group, and a nitro group.
 7. The organometallic compound of claim1, wherein in Formula 1, at least one of R₄₅ and R₄₆ is not a hydrogen.8. The organometallic compound of claim 1, wherein in Formula 1, R₄₅ andR₄₆ are different.
 9. The organometallic compound of claim 1, wherein inFormula 1, the first ligand is represented by any one of Formulae 2A-1to 2A-45:

in Formulae 2A-1 to 2A-45, Z₁, Z₂, Z₁₁ to Z₁₃, and Q₄₆ to Q₄₉ are eachindependently selected from a hydrogen, a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, carboxylic acid group or asalt thereof, sulfonic acid group or a salt thereof, phosphoric acidgroup or a salt thereof, —SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxygroup; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substitutedwith at least one selected from a deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, carboxylic acid group or asalt thereof, sulfonic acid group or a salt thereof, phosphoric acidgroup or a salt thereof, a phenyl group, a naphthyl group, a pyridinylgroup, and a pyrimidinyl group; a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and a phenyl group, a naphthyl group, afluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; aa1 is an integer selected from 1 to 4; ab1and ab2 are each independently integers selected from 1 to 3; ac1 andac2 are each independently 1 or 2; and * and *′ are binding sites to Min Formula
 1. 10. The organometallic compound of claim 1, wherein thesecond ligand is represented by any one of Formulae 2B-1 to 2B-25.

in Formulae 2B-1 to 2B-25, Z₃ and Z₄ are each independently a hydrogen,a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, —SF₅, a C₁-C₂₀alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and aC₁-C₂₀ alkoxy group, each substituted with at least one selected from adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a phenyl group, anaphthyl group, a pyridinyl group, and a pyrimidinyl group; a phenylgroup, a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; aa3 and aa4 are each independently integersselected from 1 to 4; ab3 and ab4 are each independently integersselected from 1 to 3; ac3 and ab4 are each independently integers of 1or 2; and * and *′ are binding sites to M in Formula
 1. 11. Theorganometallic compound of claim 1, wherein the third ligand isrepresented by any one of Formulae 2C-1 to 2C-4 and 2D-1 to 2D-4:

in Formula 2C-1 to 2C-4 and 2D-1 to 2D-4, Z₅, Z₆, R₁ to R₄, and R₁₁ toR₁₆ are each independently selected from a hydrogen, a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group,carboxylic acid group or a salt thereof, sulfonic acid group or a saltthereof, phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group,and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxygroup, each substituted with at least one selected from a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group,carboxylic acid group or a salt thereof, sulfonic acid group or a saltthereof, phosphoric acid group or a salt thereof, a phenyl group, anaphthyl group, a pyridinyl group, and a pyrimidinyl group; a phenylgroup, a naphthyl group, a fluorenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthrolinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isooxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and * and *′ are binding sites to M.
 12. Theorganometallic compound of claim 1, wherein in Formula 2E, R₂₁ and R₂₂are each independently selected from a cyano group; a C₁-C₂₀ alkyl groupsubstituted with at least one selected from a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a phenyl group, a naphthylgroup, a pyridinyl group, and a pyrimidinyl group; a phenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group; and a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, carboxylic acid group or a saltthereof, sulfonic acid group or a salt thereof, phosphoric acid group ora salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a pentalenyl group, an indenyl group, a naphthyl group, anazulenyl group, a heptalenyl group, an indacenyl group, an acenaphthylgroup, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenylgroup, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a naphthacenyl group, apicenyl group, a perylenyl group, a pentaphenyl group, a hexacenylgroup, a pentacenyl group, a rubicenyl group, a coronenyl group, anovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aphthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group;wherein, Q₃₁ to Q₃₇ are each independently selected from a hydrogen, adeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, carboxylic acid group or a salt thereof, sulfonic acid group or asalt thereof, phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenylgroup, a chrysenyl group, a carbazolyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a pyridinyl group, a pyrimidinyl group, a triazinyl group, aquinolinyl group, an isoquinolinyl group, a quinazolinyl group, and aquinoxalinyl group; at least one selected from R₂₁ and R₂₂ is selectedfrom a cyano group; a C₁-C₂₀ alkyl group substituted with at least oneselected from a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, carboxylic acid group or a salt thereof,sulfonic acid group or a salt thereof, phosphoric acid group or a saltthereof, a phenyl group, a naphthyl group, a pyridinyl group, and apyrimidinyl group; a pentalenyl group, an indenyl group, a naphthylgroup, an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; and a pentalenyl group, an indenyl group, anaphthyl group, an azulenyl group, a heptalenyl group, an indacenylgroup, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group,a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a pyrrolyl group, a thiophenyl group, afuranyl group, an imidazolyl group, a pyrazolyl group, a thiazolylgroup, an isothiazolyl group, an oxazolyl group, an isooxazolyl group, apyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, an isoindolyl group, an indolyl group, an indazolyl group, apurinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom a deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, carboxylic acid group or a salt thereof, sulfonic acidgroup or a salt thereof, phosphoric acid group or a salt thereof, aC1-C20 alkyl group, a C1-C20 alkoxy group, a phenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-fluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzooxazolyl group, an isobenzooxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group.
 13. The organometallic compoundof claim 1, wherein the third ligand is represented by Formula 2E(1) or2E(2):

in Formula 2E(1) and 2E(2), descriptions of Z₅, Z₆, Z₃₂, and b2 are thesame as described in claim 1, X₃₁ is N or CR₃₁, X₃₂ is N or CR₃₂, X₃₃ isN or CR₃₃, X₃₄ is N or CR₃₄, X₃₅ is N or CR₃₅, X₃₆ is N or CR₃₆, X₃₇ isN or CR₃₇, X₃₈ is N or CR₃₈, and at least one of X₃₁ to X₃₈ is N; andR₃₁ to R₃₈ are each independently the same as described for R₁.
 14. Theorganometallic compound of claim 1, wherein the third ligand isrepresented by any one of Formulae 2E-1 to 2E-25:

in Formulae 2E-1 to 2E-25, Z₅, Z₆, R₃₁ to R₃₈, and Q₅₂ to Q₅₅ above areeach independently selected from a hydrogen, a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and aC₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group,each substituted with at least one selected from a deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group,an amidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a phenyl group, a naphthylgroup, a pyridinyl group, and a pyrimidinyl group; a phenyl group, anaphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenylgroup, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isooxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzooxazolyl group, an isobenzooxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isooxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group, eachsubstituted with at least one selected from a deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, carboxylic acidgroup or a salt thereof, sulfonic acid group or a salt thereof,phosphoric acid group or a salt thereof, a C1-C20 alkyl group, a C1-C20alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolylgroup, a thiophenyl group, a furanyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isooxazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolylgroup, an indazolyl group, a purinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzooxazolylgroup, an isobenzooxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group; and—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇); wherein, Q₁ to Q₇ are eachindependently selected from hydrogen, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, and a naphthyl group; d1 is an integerselected from 1 to 4; d2 is an integer selected from 1 to 5; d3 is aninteger selected from 1 to 3; d4 is 1 or 2; and d5 is an integerselected from 1 to
 7. 15. The organometallic compound of claim 1,wherein the n1 is 0 or
 1. 16. The organometallic compound of claim 1,wherein the organometallic compound is represented by Formula 1A:

in Formula 1A, R₄₃, R₄₅, and R₄₆ are each independently selected from ahydrogen, —F, a cyano group, a nitro group, —SF₅, a methyl group, anethyl group, a propyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, anisohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptylgroup, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, ann-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group,an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonylgroup, an n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group and a triazinyl group; and a methylgroup, an ethyl group, a propyl group, an n-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, ann-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptylgroup, an n-octyl group, an isooctyl group, a sec-octyl group, atert-octyl group, an n-nonyl group, an isononyl group, a sec-nonylgroup, a tert-nonyl group, an n-decanyl group, an isodecanyl group, asec-decanyl group, a tert-decanyl group, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, a phenyl group,a naphthyl group, a pyridinyl group, a pyrimidinyl group and a triazinylgroup, each substituted with at least one selected from —F, a cyanogroup, and a nitro group; wherein both R₄₅ and R₄₆ are not —F; both R₄₅and R₄₆ are not a hydrogen; and n2 is 2 or
 3. 17. The organometalliccompound of claim 1, wherein n1 is 1 or 2; L₁ is selected from a ligandrepresented by Formula 2A-19, a ligand represented by Formula 2B-1, anda ligand represented by Formula 2E-17:

In Formulae 2A-19, 2B-1, and 2E-17, Z₁ to Z₆, R₃₁ to R₃₆, and R₃₈ areeach independently selected from a hydrogen, —F, a cyano group, a nitrogroup, —SF₅, a methyl group, an ethyl group, a propyl group, an n-butylgroup, an isobutyl group, a sec-butyl group, a tert-butyl group, ann-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, an n-hexyl group, an isohexyl group, a sec-hexyl group, atert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptylgroup, a tert-heptyl group, an n-octyl group, an isooctyl group, asec-octyl group, a tert-octyl group, an n-nonyl group, an isononylgroup, a sec-nonyl group, a tert-nonyl group, an n-decanyl group, anisodecanyl group, a sec-decanyl group, a tert-decanyl group, a methoxygroup, an ethoxy group, a propoxy group, a butoxy group, a pentoxygroup, a phenyl group, a naphthyl group, a pyridinyl group, apyrimidinyl group, and a triazinyl group; and a methyl group, an ethylgroup, a propyl group, an n-butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, an n-pentyl group, an isopentyl group, asec-pentyl group, a tert-pentyl group, an n-hexyl group, an isohexylgroup, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, anisoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octylgroup, an isooctyl group, a sec-octyl group, a tert-octyl group, ann-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group,an n-decanyl group, an isodecanyl group, a sec-decanyl group, atert-decanyl group, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentoxy group, a phenyl group, a naphthyl group, apyridinyl group, a pyrimidinyl group and a triazinyl group, eachsubstituted with at least one selected from —F, a cyano group, and anitro group, and aa1, aa3, aa4, and ac2 are each independently 1 or 2.18. The organometallic compound of claim 1, wherein the organometalliccompound is any one selected from Compounds 1 to 22:


19. An organic light-emitting device comprising a first electrode; asecond electrode; and an organic layer disposed between the firstelectrode and the second electrode, wherein the organic layer comprisesan emission layer and the organometallic compound of claim
 1. 20. Theorganic light-emitting device of claim 19, wherein the organiclight-emitting device emits blue light having a maximum emissionwavelength in a range of about 440 nanometers to about 500 nanometers,an x-color coordinate in a range of about 0.16 to about 0.22, and ay-color coordinate in a range of about 0.10 to about 0.40.